Polyamide resin composition

ABSTRACT

The present invention provides a polyamide resin composition which has low water absorption and simultaneously has satisfactory combustion properties. Illustrative compositions contain 20-80 parts by weight of polyamide resin and 80-20 parts by weight of polyphenylene ether resin or a mixture of this resin and polystyrene resin, as well as 0.01-10 parts by weight of a compatibilizer, 1-50 parts by weight of an uncured phenol novolak resin, and 0-80 parts by weight of a rubber component wherein the weights of the compatibilizer, uncured phenol novolak resin and rubber component is based on a total of 100 parts by weight of polyamide and polyphenylene ether resins.

This is a divisional of application Ser. No. 08/616,329 filed on Mar.11, 1996, now U.S. Pat. No. 5,670,576.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to polyamide resin compositions. Thecompositions further comprise polyphenylene ether resins and uncuredphenol novolak resins.

2. Brief Description of the Related Art

As polyamide resins (abbreviated hereinafter as PA) shows outstandingheat resistance, mold workability, etc., it is ordinarily used as acombined resin composition with polyphenylene ether resins (abbreviatedhereinafter as PPE) for application in automobile components,electrical/electronic components, mechanical components, etc., and itcan be expected to be used in an even broader range of fields in thefuture. However, due to the water-absorbing properties of PA, it has thedisadvantage of showing poor dimensional stability. Moreover, PA alsoshows poor flame resistance, so it is ordinarily used after adding flameretardants of the phosphorus or halogen class, etc. Nevertheless, incompositions with halogen-type flame retardants added, when suchcompositions are melted and burned during manufacturing, hydrogen halideis produced, giving rise to concerns about toxicity and environmentalproblems. Moreover, phosphorus-type flame retardants are relativelyinefficient, and when they are added in large amounts, they tend tocause plasticization and decomposition of the resin.

Various attempts have been made to improve the water absorption anddimensional instability of PA, such as a composition with phenoxy resinadded (Japanese Laid-Open Patent No. 91-237160) and a composition withpolyphenylene sulfide resin added (Japanese Laid-Open Patent No.94-200148). However, although these resin compositions show low waterabsorption, they cannot simultaneously provide satisfactory flameresistance.

For this reason, the purpose of the present invention is to provide a PAresin composition which shows low water absorption and simultaneouslyprovides satisfactory flame resistance.

SUMMARY OF THE INVENTION

The inventors of the present invention conducted thorough research onPA-type resin compositions and discovered that when uncured phenolnovolak resin is added to PA-type resin/PPE-type resin, not only ismoisture absorption low, but the resin also shows satisfactory flameresistance, thus arriving at the present invention.

Specifically, the present invention provides a polyamide resincomposition, characterized by containing:

(A) 20-80 parts by weight of polyamide resin and

(B) 80-20 parts by weight of polyphenylene ether resin or a mixture ofsaid resin and polystyrene resin, and further containing, with respectto a total of 100 parts by weight of (A) and (B):

(C) 0.01-10 parts by weight of a compatibilizer,

(D) 1-50 parts by weight of uncured phenol novolak resin, and

(E) 0-80 parts by weight of rubber components.

DETAILED DESCRIPTION OF THE INVENTION

The polyamide resin which is used as component (A) in the presentinvention is a polyamide having as its main components aminocarboxylicacid, lactam, or diamine and dicarboxylic acid. Specific examples ofthese components include lactams such as epsilon-caprolactam,enantholactam, and omega-laurolactam, aminocarboxylic acids such as11-aminoundecanoic acid and 12-aminododecanoic acid, diamines such astetramethylenediamine, hexamethylenediamine, undecamethylenediamine,dodecamethylenediamine, 2,2,4-/2,4,4-trimethylhexamethylenediamine,5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine,1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane,bis-p-aminocyclohexylmethane, bis-p-aminocyclohexylpropane, andisophoronediamine, and dicarboxylic acids such as adipic acid, subericacid, azelaic acid, sebacic acid, didodecanoic acid,1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, anddimer acid. These components may be used either individually or in theform of mixtures of two or more types, and either polyamide homopolymersor copolymers obtained in this manner may be used in the presentinvention. Specific examples of the polyamides used in the presentinvention include polycaproamide (nylon 6), polyhexamethylene adipide(nylon 66), polyhexamethylene sebacide (nylon 610), polyundecanamide(nylon 11), polydodecanamide (nylon 12), as well as copolymers andmixtures of these polyamides. Among these substances, nylon 66 ispreferred.

Any commonly known substance may be used as the PPE resin of component(B). PPE resin is a generic term, indicating, for example, the polymershown in General Formula (I) below: ##STR1##

In the formula, R₁, R₂, R₃, and R₄ are independent hydrogen atoms,halogen atoms, alkyl groups, or alkoxy groups, or haloalkyl orhaloalkoxy groups having at least 2 carbon atoms between the halogenatom and the phenyl ring and denote monovalent substituents selectedfrom among substances which do not contain tertiary α-carbon, and n isan integer indicating the degree of polymerization, and the polymershown in the above General Formula (I) may be used either alone or inthe form of a copolymer consisting of a combination of 2 types or more.As a specific example, it is preferred that R₁ and R₂ be alkyl groupshaving 1 to 4 carbon atoms and that R₃ and R₄ be hydrogen atoms or alkylgroups having 1 to 4 carbon atoms. Examples includepoly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene)ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether,poly(2-methyl-6-propyl-1,4-phenylene) ether,poly(2,6-dipropyl-1,4-phenylene) ether,poly(2-ethyl-6-propyl-1,4-phenylene) ether, etc.Poly(2,6-diethyl-1,4-phenylene) ether is particularly preferred as aPPE. Moreover, an example of a polyphenylene ether copolymer is acopolymer partially containing an alkyl-trisubstituted phenol such as2,3,6-trimethylphenol in the polyphenylene ether repeated unitAlternatively, these polyphenylene ethers may also be copolymers withstyrene compounds grafted on. Examples of the styrene compound graftedonto the aforementioned polyphenylene ether in order to produce styrenecompound grafted polyphenylene ether include copolymers obtained bygraft polymerization of styrene, α-methylstyrene, vinyltoluene, andchlorostyrene.

A group of polyphenylene ethers which are particularly preferred for thepresent invention includes substances having a C₁ to C₄ alkylsubstituent in the two ortho positions with respect to the ether oxygenmolecule. Examples of this group include the following:

Poly(2,6-dimethyl-1,4-phenylene) ether;

Poly(2,6-diethyl-1,4-phenylene) ether;

Poly(2-methyl-6-ethyl-1,4-phenylene) ether;

Poly(2,6-dipropyl-1,4-phenylene) ether;

and Poly(2-ethyl-6-propyl-1,4-phenylene) ether.

In the present invention, component (B) is the aforementionedpolyphenylene ether resin or a mixture of this and polystyrene (PS)resin. Examples of polystyrene resins include styrene or itsderivatives, such as homopolymers and copolymers includingp-methylstyrene, α-methylstyrene, α-methyl-p-methylstyrene,chlorostyrene, and bromostyrene. Moreover, one may also use a rubbermodified polystyrene (HIPS) composed of 70-99% by weight of theaforementioned styrene compound and 1-30% by weight of diene rubber.Examples of the diene rubber making up HIPS include monomers ofconjugated diene compounds such as butadiene, isoprene, and chloroprene,copolymers of conjugated diene compounds and unsaturated nitrilecompounds or styrene compounds, as well as natural rubbers, and 1 or 2or more of these substances may be used. Polypropylene andbutadiene-styrene copolymer are particularly preferred. HIPS may beobtained by emulsion polymerization, suspension polymerization, bulkpolymerization, solution polymerization, or a combination of thesemethods. Moreover, other examples of polystyrene resins includepolystyrene thermoplastic elastomers such asstyrene-acrylonitrile-acrylate copolymer, EPDM-type rubber modifiedpolystyrene, acrylic rubber modified styrene-acrylonitrile copolymer,hydrogenated styrene-butadiene block copolymer.

PPE resin and PS resin may be blended at any desired ratio, but theusual blending ratio of these substances is 90-0 parts by weight of PSresin with respect to 10-100 parts by weight of PPE resin. One shouldpreferably use 90-10 parts by weight of PS resin with respect to 10-90parts by weight of PPE resin.

The above mentioned components (A) and (B) should be blended in theamount of 80-20 parts by weight of (B) with respect to 20-80 parts byweight of (A), with a ratio of 55-35 parts by weight of (B) to 65-45parts by weight of (A) being preferred. If the amount of (A) used is toogreat, water absorption will increase and dimensional stability will beadversely affected, and mechanical strength will also show a tendency todecrease, and if the amount of (B) is too great, layer reversal willoccur and it will be impossible to obtain the desired physicalproperties.

The resin composition of the present invention should contain 0.01 partsby weight or more with respect to a total of 100 parts by weight of theaforementioned components (A) and (B), with the amount of 0.1 parts byweight or more being preferred, and component C, the compatibilizer,should preferably be included in the amount of 10 parts by weight orless, and preferably 5 parts by weight or less. If the amount of thecompatibilizer is too small, compatibilization of components (A) and (B)will be insufficient, leading to unsatisfactory mechanical strength,chemical resistance, and workability. On the contrary, if it is toogreat, die swelling will occur during manufacturing, causing majorproblems in processing and making it impossible to improve properties inan optimal manner.

A commonly known compatibilizer may be used together with PA and PPE asthe compatibilizer of component (C). Examples of preferredcompatibilizers are listed below. First of all, the first groupcomprises (i) unsaturated carboxylic acid and its derivatives, such asthe compounds presented in Japanese Laid-Open Patent No. 81-26913. Thisunsaturated carboxylic acid and its derivatives are compounds in whichthe molecule contains (a) carbon-carbon double bonds or triple bonds and(b) compounds containing carboxylic acid groups, acid anhydride groups,acid amide groups, imide groups, carboxylic acid ester groups, or epoxygroups. Examples of these compounds are maleic anhydride, maleic acid,fumaric acid, maleimide, maleic acid hydrazide, and reaction products ofmaleic anhydride and diamines, and they have structures such as thatshown in the following Formulas (II): ##STR2##

Wherein R is an aliphatic or aromatic group. Examples includemethylnadic anhydride, dichloromaleic anhydride, maleamide, natural oilsand fats such as soybean oil, tung oil, castor oil, linseed oil,hampseed oil, cottonseed oil, sesame oil, rapeseed oil, peanut oil,camellia oil, olive oil, palm oil, and sardine oil, epoxidized naturaloils and fats such as epoxidized soybean oil, unsaturated carboxylicacids such as acrylic acid, butenoic acid, crotonic acid, vinyl acetate,methacrylic acid, pentenoic acid, angelic acid, tiburinic acid,2-pentenoic acid, 3-pentenoic acid, α-ethylacrylic acid,β-methylcrotonic acid, 4-pentenoic acid, 2-hexenoic acid,2-methyl-2-pentenoic acid, 3-methyl-2-pentenoic acid, α-ethylcrotonicacid, 2,2-dimethyl-3-butenoic acid, 2-heptenoic acid, 2-octenoic acid,4-decenoic acid, 9-undecenoic acid, 10-undecenoic acid, 4-dodecenoicacid, 5-dodecenoic acid, 4-tetradecenoic acid, 9-tetradecenoic acid,9-hexadecenoic acid, 2-octadecenoic acid, 9-octadecenoic acid,eicosenoic acid, docosenoic acid, erucic acid, tetracosenoic acid,mycolipenoic acid, 2,4-pentadienoic acid, 2,4-dodecadienoic acid,9,12-hexadecadienoic acid, 9,12-octadecadienoic acid, hexadecatrienoicacid, linoleic acid, linolenic acid, octadecatrienoic acid,eicosadienoic acid, eicosatrienoic acid, eicosatetraenoic acid,ricinoleic acid, eleostearic acid, oleic acid, eicosapentenoic acid,erucic acid, docosadienoic acid, docosatrienoic acid, docosatetraenoicacid, docosapentenoic acid, tetracosenoic acid, hexacosenoic acid,hexacosadienoic acid, octacosenoic acid, and toraacontenic acid, orsubstances consisting of esters of these unsaturated carboxylic acids,acid amides, anhydrides, or low polymers such as butadiene and isoprene(such as substances having an average molecular weight of approximately500 to 10,000) or high molecular weight polymers (such as substanceshaving an average molecular weight of 10,000 or above with maleicanhydride or phenols added), or substances having a carboxylic acidgroup or epoxy group introduced.

Next, the second group of compatibilizers comprises (ii) saturatedaliphatic polycarboxylic acid and its derivatives, such as the compoundspresented in Japanese Laid-Open Patent No. 86-502195. In this case, theterm saturated aliphatic polycarboxylic acid or its derivatives refersto a compound having the following Formula (III):

    (R.sup.I O).sub.m R*(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s.(III)

In Formula (II), R* indicates a straight-chain or branched-chainsaturated aliphatic hydrocarbon group having 2 to 20 carbon atoms, andpreferably 2 to 10 carbon atoms,

R^(I) indicates a hydrogen atom or alkyl group, aryl group, or acylgroup or a carbonyldioxy group (here, with 1 to 10 carbon atoms, andpreferably 1 to 6 carbon atoms, with 1 to 4 being even more preferable),with a hydrogen atom being particularly preferred,

R^(II) indicates a hydrogen atom, an alkyl group, or an aryl group(here, having 1 to 20 carbon atoms, and preferably 1 to 10),

R^(III) and R^(IV) indicate hydrogen atoms or alkyl or aryl groups(here, with 1 to 10 carbon atoms, and preferably 1 to 6 carbon atoms,with 1 to 4 being particularly preferred,

m=1,

n+s≧2, and preferably, n+s=2 or 3,

n≧0,

s≧0,

(R^(I) O) is located at the α or β position relative to the carbonylgroup, and 2 to 6 carbon atoms are present between at least 2 carbongroups.

Specific examples of the above mentioned derivatives of saturatedaliphatic polycarboxylic acid include ester compounds, amide compounds,anhydrides, hydrates, salts, etc., of saturated aliphatic polycarboxylicacids.

Examples of saturated aliphatic polycarboxylic acids include citricacid, malic acid, and agaricic acid. Examples of acid ester compoundsinclude acetic esters or mono or distearyl esters of citric acid.Examples of acid amide compounds include N,N'-diethylamides,N,N'-dipropylamides, N-phenylamides, N-dodecylamides, andN,N'-didodecylamides of citric acid and N-dodecylamides of malic acid.Examples of salts include potassium salts and calcium salts.

The third group of compatibilizers comprises (iii) compounds whichsometimes have (a) a mercapto group or (b) a carboxyl group, acidanhydride group, acid amide group, imide group, or carboxylic acid estergroup in the same molecule. Specific examples includemercaptopolycarboxylic acids such as thiomalic acid and thiocitric acid,compounds in which the carboxyl groups of these mercaptopolycarboxylicacids are substituted with an N,N'-dialkylamine group, an N-alkylamidegroup, an N-arylamide group, or an alkyl ester group, epoxy compoundssuch as 1,2-epoxy-3-mercaptopropane and4-di(2,3-epoxypropyl)aminothiophenol, amines such as1-amino-2-mercaptoethane and 4-aminothiophenol,mercapto-group-containing alcohols such as 2-mercaptoethanol and3-mercapto-1,2-propanediol, and mercaptophenols. Mercaptopolycarboxylicacids such as thiomalic acid and thiocitric acid are particularlypreferred.

The fourth group of compatibilizers comprises (iv) thiocarboxylic acidanhydrides having the Formula (IV) shown below: ##STR3##

In the above formula (IV), R^(a) and R^(b) are hydrogen atoms or alkylgroups, alkoxy groups, cycloalkyl groups, alkenyl groups, aryl groups,arylene groups, or alkylene groups having 1 to 12 carbon atoms), withspecific examples of substances which may be used includingmonothiomaleic anhydride synthesized by the methods described by H. D.Scharf and M. Verbeek, Angew. Chem. Int Ed. Engl., 6, 37 4 (1967) andTamura et al. in Synthesis, 559 (1977).

The fifth group of compatibilizers comprises (v) saturated bis(acidanhydride) compounds having the Formulas (V), (VI), and (VI) shownbelow: ##STR4##

In the above formulas, R¹ to R⁶ are independent hydrogen atoms, halogenatoms, or alkyl, alkoxy, cycloalkyl, alkenyl, aryl, arylene, or alkylenegroups having 1 to 12 carbon atoms or tetracarboxylic acids selectedfrom among those having the following Formula (VIII): ##STR5##

In the above Formula (VIII), R¹ -R⁶ are independent hydrogen atoms,halogen atoms, or alkyl, alkoxy, cycloalkyl, alkenyl, or aryl groupshaving 1 to 12 carbon atoms.

These compatibilizers may be used either individually or in combinationsof two or more. The compatibilizer used should preferably be selectedfrom the above groups (i) and (ii).

Next, the resin composition of the present invention also contains (D)uncured phenol novolak resin. In this case, uncured phenol novolak resinrefers to a substance which, in addition to unmodified uncured phenolnovolak resin (referred to in the following simply as uncured phenolnovolak resin), also contains modified uncured phenol novolak resin.

Uncured phenol novolak resin is a resin having the structure shown inFormula (D() below: ##STR6##

In the above Formula (D(IX), p indicates degree of polymerization, whichis ordinarily 2-10, and it is obtained by polymerization of phenols andformalin using an acid catalyst. Ordinarily, substances having amolecular weight of 500-1,000, a solution viscosity of 50-300 CST (in a50% ethanol solution), and a softening point of 95°-130° C. arepreferred for the present invention.

Concerning the modified uncured phenol novolak resin of the invention,the aforementioned uncured phenol novolak resin should be modified resinof at least one of the following types: an aromatic hydrocarbon resin(such as cresol, xylenol, p-t-butylphenol, etc.), an epoxy resin, or aboric acid modified resin. Moreover, 1 to 50% by weight of the uncuredphenol novolak resin should preferably be modified.

(D) The uncured phenol novolak resin should be blended in the amount of1 part by weight or above, and preferably 2.5 parts by weight or aboveand 50 parts by weight or below, and preferably 20 parts by weight orbelow with respect to 100 parts by weight of the aforementionedcomponent (A). If the blending ratio of (D) the uncured phenol novolakresin is too high, the thermal resistance and mechanical strength of thePA resin will decrease markedly, and if it is too low, the desired lowwater resistance and flame retardant effect will be impossible toobtain.

The composition of the present invention may contain (E) a rubbercomponent, for example, in the amount of 80 parts by weight or less, andpreferably 3 to 20 parts by weight with respect to a total of 100 partsby weight of components (A) and component (B) as optional ingredients.

The rubber component contains natural or synthetic polymer materialswhich are elastic at room temperature. Specific examples include naturalrubber, butadiene polymer, styrene-isoprene copolymer, butadiene-styrenecopolymer (including all types of random copolymers, block copolymers,graft copolymers, etc.), isoprene polymer, chlorobutadiene polymer,butadiene-acrylonitrile copolymer, isobutylene polymer,isobutylene-butadiene copolymer, isobutylene-isoprene copolymer, acrylicacid ester polymer, ethylene-propylene copolymer,ethylene-propylene-diene copolymer, thiokol rubber, polysulfide rubber,polyurethane rubber, polyether rubber (such as polypropylene oxide), andepichlorohydrin rubber.

These rubber components may be manufactured by any polymerization method(such as emulsion polymerization or solution polymerization) and usingany desired catalyst (such as peroxide, trialkylaluminum, halogenatedlithium, or a nickel catalyst). Moreover, substances having variousdegrees of crosslinking, substances having various proportions ofmicrostructures (such as cis structures, trans structures, vinyl groups,etc.), or substances having varying average rubber particle diametersmay be used. Furthermore, any type of copolymer, such as randomcopolymers, block copolymers, and graft copolymers, may be used. Also,in producing these rubber components, it is possible to use copolymerswith monomers such as olefins, dienes, aromatic vinyl compounds,(meth)acrylic acid, (meth)acrylate ester, etc. Any desired method ofcopolymerization, such as random copolymerization, blockcopolymerization, or graft copolymerization, may be used. Specificexamples of these monomers include ethylene, propylene, styrene,chlorostyrene, α-methylstyrene, butadiene, isobutylene, chlorobutadiene,butene, methyl acrylate, acrylic acid, ethyl acrylate, butyl acrylate,methyl methacrylate, and acrylonitrile.

Furthermore, partially modified rubber components may also be used, suchas hydroxy- or carboxy-terminal modified polybutadiene, partiallyhydrogenated styrene-butadiene block copolymer, or partiallyhydrogenated styrene-isoprene block copolymer.

In the present invention, the HIPS, etc., having a styrene compound asits main component may be contained in the polystyrene resin of theaforementioned component (B) rather than the rubber component ofcomponent (E).

The composition of the present invention may also contain (F) anantioxidant or (G) a metallic salt stabilizer as optional components.

The (F) antioxidant may be any well-known substance, with examplesincluding tetrakis methylene-3-(dodecylthio)propionate!methane, tetrakismethylene-3,5-di-t-butyl-4-hydroxyhydrocinnamate!methane, or n-octadecyl(3', 5'-di-t-butyl-4-hydroxyphenyl)propionate; and commercial substancessuch as Irganox 1076 (commercial name, manufactured by Ciba-Geigy Co.),Ultranox 257 (commercial name, manufactured by General Electric Co.),Seenox 412S (commercial name, manufactured by Argus Chemical Co.),Irganox MD-1024 (commercial name, manufactured by Ciba-Geigy Co.), MARKA060 (commercial name, manufactured by Adeka Agasu Kagaku K.K.), orHaugard XL-1 (commercial name, Uniroyal Chemical Co.).

The (F) antioxidant is ordinarily contained in the amount of 5 parts byweight or less, and preferably 2 parts by weight or less, with respectto a total of 100 parts by weight of components (A) and (B).

Moreover, (G) as the metallic salt stabilizer, a metallic salt havingFormula (X) below may be used:

    (X) M.sup.Y+.sub.n X.sup.z-.sub.ny/z                       (X)

In the above Formula (X), M indicates a metal selected from amongcopper, nickel, tin, and cerium, X is selected from among a halogen atom(Cl, Br, F, I) or a carboxylate residue such as a stearate residue (C₁₇H₃₅ COO) or acetate residue (CH₃ COO), n indicates an integer from 1 to8 indicating the number of cations, ny/z indicates the number of anions,y indicates the number of cations of the metal M, and z indicates thecation charge of X.

Specific examples include CuCl₂, CuI (cuprous iodide), copper acetate,and cerium stearate. Among these substances, CuI is preferred. CuI isavailable on the market, but it may also be prepared by sedimentation orisolation of salt via a reaction of metallic copper and HI. Moreover, inthe case of use of CuI, KI (potassium iodide) may be used in combinationas a CuI stabilizer.

Furthermore, for example, in the presence of a halogenate ion such asKI, one may use a metallic carboxylate such as cerium stearate, and inthis case, it is possible to induce the production of metal halogenates.

(G) The metallic salt stabilizer is ordinarily mixed in the amount of 5parts by weight or less, and preferably 2 parts by weight or less, withrespect to a total of 100 parts by weight of components (A) and (B). (G)the metallic salt stabilizer is effective at a concentration ofapproximately 200 ppm, with an amount of 0.001 arts by weight or abovebeing more preferable.

In addition to the above mentioned components, depending on the intendeduse, one may also add pigments, dyes, reinforcing materials (metalfibers, metal flakes, carbon fibers, etc.), fillers (talc, carbon black,silica, titanium oxide, etc.), thermal stabilizers, optical stabilizers,ultraviolet absorbers, weatherproofing agents, lubricants, moldreleasing agents, crystal nucleating agents, plasticizers, fluidityimproving agents, or antistatic agents to the resin composition of thepresent invention. Moreover, in order to further increase the flameretardant effect, flame retardants may also be added.

There are no particular restrictions on the method used to manufacturethe resin composition of the present invention, and any ordinary methodmay be satisfactorily used. However, the method of melt mixing isgenerally preferred. The use of small amounts of solvents is alsopossible, but this is generally unnecessary. Particular examples of theequipment which may be used include extruders, Banbury mixers, rollers,and kneaders, and these may be operated on a batch or continuous basis.There are no particular restrictions on the mixing order of thecomponents used.

EXAMPLES

The following is a detailed explanation of the present invention bymeans of practical examples, but the invention is not restricted tothese examples.

The following compounds were used in the practical examples.

Component (A)

PA resin: Nylon 6,6 having a relative viscosity of 2.9, a terminal aminogroup content of 5.5×10⁻⁵ moles/g, and a terminal carboxyl group contentof 7.2×10⁻⁵ moles/g.

Component (B)

PPE: Poly(2,6-dimethyl-1,4-phenylene) ether having an intrinsicviscosity (chloroform, 30° C.) of 0.46 dl/g (manufactured by G. E.Plastics).

Component (C)

Citric acid

Component (D)

PN-1: Uncured phenol novolak resin (softening point 125° C., solutionviscosity 250 CST, manufactured by Sumitomo as grade PR-50731)

PN-2: Boric acid-modified phenol novolak resin (uncured phenol novolakresin modified with boric acid, softening point 115° C., solutionviscosity 80 CST, manufactured by Sumitomo as grade RX-53101)

Optional components (E)

SEPS: Hydrogenated styrene-isoprene block copolymer (manufactured byKurarray as grade SEPTON 1001)

Practical Examples 1 to 3 and Comparison Example 1

The components were mixed at the ratios shown in Table 1 (weightratios), and using a biaxial extruder equipped with a reduced pressurevent, they were extruded as described below in order to form pellets.Specifically, extrusion was carried out in three separate stages. In thefirst stage, PPE, SEPS, and citric acid were blended, and the mixturewas then extruded at a temperature of 300° C. to form pellets. Next, PAwas uniformly blended into the pellets obtained in Step 1, and thismixture was extruded at a temperature of 280° C. to form pellets (Step2). Next, phenol novolak resin was uniformly blended into the pelletsobtained in Step 2, and this mixture was extruded at a temperature of280° C. to make the final pellets.

These final pellets were molded in an injection molding machine set to acylinder temperature of 280° C. and a metal mold temperature of 80° C.to make test pieces. Using the test pieces thus obtained, the followingevaluation tests were conducted. The results are shown in Table 1.

(1) Flame resistance test

According to the combustion test for the Bulletin 94 MaterialsClassification of Underwriters Laboratories Corporation (UL94 test),evaluation was conducted by VB (vertical burning) (with a 1/16 inch testpiece). In UL94 VB, combustion tests were conducted using 5 test pieces,and the average combustion time and presence or absence of dripping wereinvestigated during 10 combustions.

(2) Water absorption ratio

An ASTM No. 1 dumbbell test specimen was immersed for 7 days in water at85° C., and the water absorption ratio was determined by comparingweights before and after the test.

                  TABLE 1    ______________________________________                Practical                         Practical                                  Practical    Components  Example  Example  Example                                         Comparison    (parts by weight)                1        2        3      Example 1    ______________________________________    (A) PA          53       53     53     53    (B) PPE         40       40     40     40    (C) Citric acid 0.7      0.7    0.7    0.7    (D) PN-1        5        10     --     --        PN-2        --       --     10     --    (E) SEBS        7        7      7      7    Evaluation tests    Combustion test                20.4     13.5     10.2   60.5    (UL94 VB)    Average combustion    time (sec)    Dripping    Yes      Yes      Yes    Yes    Water absorption                3.54     3.07     3.10   4.25    rate (%)    ______________________________________

As the PA resin composition of the present invention shows both lowwater absorption and outstanding combustion properties, it is consideredto be of high practical value. Moreover, as the desired combustionproperties can be obtained without using halogen-type flame retardants,the invention is also favorable because it causes little environmentalpollution.

We claim:
 1. A polyamide resin composition comprising:(A) 20-80 parts byweight of polyamide resin; (B) 80-20 parts by weight of polyphenyleneether resin or a mixture of said polyphenylene ether resin andpolystyrene resin;and with respect to a total of 100 parts by weight of(A) and (B), further comprising: (C) 0.01-10 parts by weight of acompatibilizer wherein the compatibilizer is an unsaturated carboxylicacid or a derivative of an unsaturated carboxylic acid; (D) 1-50 partsby weight of uncured phenol novolak resin wherein the uncured phenolnovolak resin is at least partly modified by boric acid; and (E) 0-80parts by weight of rubber components.
 2. The polyamide resin compositionof claim 1, wherein the compatibilizer contains (a) a carbon-carbondouble bonds or a carbon-carbon triple bond and (b) a carboxylic acidgroup, anhydride group, amide group, imide group, carboxylic acid estergroup, or epoxy group.
 3. The polyamide resin composition of claim 2,wherein the compatibilizer is selected from the group consisting ofmaleic anhydride, maleic acid, fumaric acid, maleimide, maleic acidhydrazide, reaction products of maleic anhydride and diamines, andcompatibilizers having structures ##STR7## wherein R is an aliphatic oraromatic group.
 4. The polyamide resin composition of claim 2, whereinthe compatibilizer is selected from the group consisting of maleicanhydride, maleic acid, fumaric acid, and maleimide.
 5. The polyamideresin composition of claim 2, wherein the compatibilizer is selectedfrom the group consisting of methylnadic anhydride, dichloromaleicanhydride, maleamide, soybean oil, tung oil, castor oil, linseed oil,hampseed oil, cottonseed oil, sesame oil, rapeseed oil, peanut oil,camellia oil, olive oil, palm oil, sardine oil, epoxidized soybean oil,acrylic acid, butenoic acid, crotonic acid, vinyl acetate, methacrylicacid, pentenoic acid, angelic acid, tiburinic acid, 2-pentenoic acid,3-pentenoic acid, α-ethylacrylic acid, β-methylcrotonic acid,4-pentenoic acid, 2-hexenoic acid, 2-methyl-2-pentenoic acid,3-methyl-2-pentenoic acid, α-ethylcrotonic acid, 2,2-dimethyl-3-butenoicacid, 2-heptenoic acid, 2-octenoic acid, 4-decenoic acid, 9-undecenoicacid, 10-undecenoic acid, 4-dodecenoic acid, 5-dodecenoic acid,4-tetradecenoic acid, 9-tetradecenoic acid, 9-hexadecenoic acid,2-octadecenoic acid, 9-octadecenoic acid, eicosenoic acid, docosenoicacid, erucic acid, tetracosenoic acid, mycolipenoic acid,2,4-pentadienoic acid, 2,4-dodecadienoic acid, 9,12-hexadecadienoicacid, 9,12-octadecadienoic acid, hexadecatrienoic acid, linoleic acid,linolenic acid, octadecatrienoic acid, eicosadienoic acid,eicosatrienoic acid, eicosatetraenoic acid, ricinoleic acid, eleostearicacid, oleic acid, eicosapentenoic acid, erucic acid, docosadienoic acid,docosatrienoic acid, docosatetraenoic acid, docosapentenoic acid,tetracosenoic acid, hexacosenoic acid, hexacosadienoic acid,octacosenoic acid, toraacontenic acid, and substances containing estersof the aforementioned compounds.
 6. The resin composition of claim 1,wherein the rubber component is selected from the group consisting ofnatural rubber, butadiene polymer, styrene-isoprene copolymer,butadiene-styrene copolymer, isoprene polymer, chlorobutadiene polymer,butadiene-acrylonitrile copolymer, isobutylene polymer,isobutylene-butadiene copolymer, isobutylene-isoprene copolymer, acrylicacid ester polymer, ethylene-propylene copolymer,ethylene-propylene-diene copolymer, thiokol rubber, polysulfide rubber,polyurethane rubber, polyether rubber, and epichlorohydrin rubber. 7.The resin composition of claim 1, wherein the rubber component is arandom copolymer, block copolymer, or graft copolymer.
 8. The resincomposition of claim 1, further comprising an antioxidant in the amountof 5 parts by weight or less with respect to a total of 100 parts byweight of components (A) and (B).
 9. The resin composition of claim 1,further comprising a metallic salt stabilizer in the amount of 5 partsby weight or less with respect to a total of 100 parts by weight ofcomponents (A) and (B).
 10. A polyamide resin composition consistingessentially of:(A) 20-80 parts by weight of polyamide resin; (B) 80-20parts by weight of polyphenylene ether resin or a mixture of saidpolyphenylene ether resin and polystyrene resin;and with respect to atotal of 100 parts by weight of (A) and (B), further consistingessentially of: (C) 0.01-10 parts by weight of a compatibilizer whereinthe compatibilizer is an unsaturated carboxylic acid or a derivative ofan unsaturated carboxylic acid; (D) 1-50 parts by weight of uncuredphenol novolak resin wherein the uncured phenol novolak resin is atleast partly modified by boric acid; and (E) 0-80 parts by weight ofrubber components.
 11. The polyamide resin composition of claim 10,wherein the compatibilizer contains (a) a carbon-carbon double bonds ora carbon-carbon triple bond and (b) a carboxylic acid group, anhydridegroup, amide group, imide group, carboxylic acid ester group, or epoxygroup.
 12. The polyamide resin composition of claim 10, wherein thecompatibilizer is selected from the group consisting of maleicanhydride, maleic acid, fumaric acid, maleimide, maleic acid hydrazide,reaction products of maleic anhydride and diamines, and compatibilizershaving structures ##STR8## wherein R is an aliphatic or aromatic group.13. The polyamide resin composition of claim 10, wherein thecompatibilizer is selected from the group consisting of maleicanhydride, maleic acid, fumaric acid, and maleimide.
 14. The resincomposition of claim 10, further consisting essentially of anantioxidant in the amount of 5 parts by weight or less with respect to atotal of 100 parts by weight of components (A) and (B).
 15. The resincomposition of claim 10, further consisting essentially of a metallicsalt stabilizer in the amount of 5 parts by weight or less with respectto a total of 100 parts by weight of components (A) and (B).